Seven Brief Lessons on Physics is a book about the joy of discovery. C
arlo Rovelli brings a playful, entertaining, and mind-bending introduction to modern physics, offering surprising—and surprisingly easy to grasp—explanations of Einstein’s general relativity, quantum mechanics, elementary particles, gravity, black holes, the complex architecture of the universe, and the role humans play in this weird and wonderful world.
‘WASTING’ TIME
In his youth Albert Einstein spent a year loafing aimlessly. You don’t get anywhere by not ‘wasting’ time–something, unfortunately, that the parents of teenagers tend frequently to forget. He was in Pavia. He had joined his family, having abandoned his studies in Germany, unable to endure the rigors of his high school there. It was the beginning of the twentieth century, and in Italy the beginning of an industrial revolution.
His father, an engineer, was installing the first electricity-generating power plants in the Paduan plains. Albert was reading Kant and attending occasional lectures at the University of Pavia: for pleasure, without being registered there or having to think about exams. It is thus that serious scientists are made.
After this he registered at the University of Zurich and immersed himself in the study of physics. A few years later, in 1905, he sent three articles to the most prestigious scientific journal of that period, the Annalen der Physik. Each of these is worthy of a Nobel Prize.
The first shows that atoms really exist. The second lays the first foundation for quantum mechanics. The third presents his first theory of relativity (known today as ‘special relativity’), the theory that elucidates how time does not pass identically for everyone.
A MASTERPIECE: THE GENERAL THEORY OF RELATIVITY
There are absolute masterpieces that moves us intensely: Mozart’s Requiem, Homer’s Odyssey, the Sistine Chapel, King Lear. To fully appreciate their brilliance may requiere a long apprenticeship, but the reward is sheer beauty–and not only this, but the opening of our eyes to a new perspective upon the world. Einstein’s jewel, the general theory of relativity, is a masterpiece of this order.
Among the numerous leaps forward in our understanding that have succeeded one another over the course of history, Einstein is perhaps unequaled.
Why?
In the first place because, once you understand how it works, the theory has a breathtaking simplicity.
[bluebox]Newton had tried to explain the reason why things fall and the planets turn. He had imagined the existence of a ‘force’ that draws all material bodies toward one another and called it ‘the force of gravity.’ How this force was exerted between things distant from each other, without there being anything between them, was unknown–and the great father of modern science was cautious of offering a hypothesis. Newton had also imagined that bodies moved through space and that space is a great empty container, a large box that enclosed the universe, an immense structure through which all objects run true until a forces obliges their trajectory to curve. What this ‘space’ was made of, this container of the world he invented, Newton could not say.
But a few years before the birth of Einstein two great British physicits, Michael Faraday and James Maxwell, had added a key ingredient to Newton’s cold world: the electromagnetic field. This field is a real entity that, difused everywhere, carries radio waves, fills space, can vibrate and oscillate like the surface of a lake, and ‘transports’ the electrical force.
Since his youth Einstein had been fascinated by this electromagnetic field that turned the rotors in the power stations built by his father, and he soon came to understand that gravity, like electricity, must be conveyed by a field as well: a ‘gravitational’ field analogous to the ‘electrical’ field must exist. He aimed at understanding how this ‘gravitational field’ worked and how it could be described with equations. And it is at this point that an extraordinary idea occurred to him, a stroke of pure genius: the gravitational field is not diffused through space; the gravitational field is that space itself. This is the idea of the general theory of relativity.
Space is no longer something distinct from matter–it is one of the ‘material’ components of the world. An entity that undulates, flexes, curves, twists.
In short, the theory describes a colorful and amazing world where universes explode, space collapses into bottomless holes, time sags, and slows near a planet, and the unbounded extensions of interstellar space ripple and sway like the surface of the sea…[/bluebox]
Related Reading:
Complement Seven Brief Lessons on Physics with Einstein’s Miracle Year.